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ANATOMY REFRESHER
2. The more complicated sub-talar joint which is made up of the bones of the talus, calcaneum and cuboid bones.
Figure 3a: Dorsiflexion Figure 3b: Plantarflexion
Movements of the ankle Movement of the true ankle joint occurs in one direction, plantar and dorsi- flexion (sagittal plane) (see figures 3a+3b, video 1). The three dimensions of the subtalar joint however allows for inversion and eversion (see figures 4a+4b, video 2) and pronation and supination (see figures 4c+4d).
The movement of eversion and its counteracting movement of inversion allows the foot to take rough ground into account without putting excess strain on the true ankle joint. There are no intra-articular ligaments or cartilages of note within either joint capsule.
Figure 4a: Inversion Figure 4b: Eversion
The neutral and the anatomical positions of the ankle are one and the same and consist of the foot positioned at a right angle to the shin. The most stable position of the ankle is fully dorsi-flexed because the talus is slightly wider anteriorly thereby stopping excess dorsi-flexion.
For the rest of the article we will consider both joints as a single joint acting together together.
Figure 4c: Pronation
when contracting eccentrically, to control the rate of pronation. This can cause trigger points to occur. The ankle consists of two main joints (see figure 2):
ankle rolls toward centre
LEFT FOOT
RIGHT FOOT
little toe
little toe
big toe
heel rotates away from center
Figure 5a: Pronation of the foot as seen from behind
little toe
Figure 4d: Supination
1. The ‘true’ ankle joint (tibiotalar joint) which is similar to a mortice and tenon joint in woodwork - this joint consists of the articular facet of the talus which articulates with the tibia and fibula bones
LEFT FOOT
ankle rolls
away from
centre
big toe
heel turns toward centre
Figure 5b: Supination of the foot as seen from behind. See video 5 under the Interactive extras section for a video showing pronation and supination in standing.
little toe
RIGHT FOOT
Muscle movements l Plantar-flexion – is due to the muscles in the posterior compartment of the calf i.e. gastrocnemius, soleus, posterior tibialis, flexors of the toes l Dorsi-flexion – is caused by the muscles in the anterior compartment of the shin i.e. tibialis anterior and extensors of the toes l Eversion – is caused by the peroneii muscles (i.e. longus, brevis and tertius) l Inversion – is down to movements of the extensors of the toes, tibialis anterior and posterior combined.
The gastrocnemius muscles are the power muscles for running. Soleus is the main muscle for walking and standing. The other muscles in gross terms manoeuvre and stabilise the foot during movement.
As with the knee, the ankle is a joint which is stable due to the array of ligaments connecting the talus and calcaneum to the tibia and fibula.
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©2011 sportEX
©2011 sportEX
©2011 sportEX
©2011 sportEX
©2011 sportEX
©2011 sportEX
©2011 sportEX
©2011 sportEX